The Orofacial Pain Research
Chronic musculoskeletal pains are among the commonest reasons for longtime disability and thus are associated with high costs for the society.

In the orofacial area temporomandibular disorders (TMD) are the most frequent chronic pain conditions. TMD is a collective term embracing chronic conditions affecting the temporomandibular joint (TMJ) or the masticatory muscles (myalgia). It affects about 5%–10% of the population and is more prevalent in women than men. In children prevalence as high as 20% has been reported. Symptoms include pain especially on function, tenderness, restricted jaw opening, joint sounds and locking as well as headache and, thus, reduces patients’ quality of life.
The main focus of the research is on orofacial pain of muscular origin, from causes to treatment in both children and adults, and its sex differences. Another area is orofacial pain in children with juvenile Idiopathic arthritis. The group also conduct pedagogic research.
The research is translational, spanning from basic research conducted in patients and matched pain-free controls via human experimental studies where pain is induced experimentally, to clinical intervention studies. The research methods include e.g. intramuscular microbiopsy, microdialysis, blood and saliva sampling for immunohistochemistry, biochemical, genomic and proteomic analyses (in collaboration with other researchers), conditioned pain modulation, exercise-induced analgesia, quantitative sensory testing (sensory and pain thresholds for warmth, cold and mechanical stimuli), transcranial magnetic stimulation (TMS), electromyography (EMG) and jaw tracking.
The Orofacial Pain Research Group is part of the larger Orofacial Neuroscience Group at the Department of Dental Medicine, which in turn collaborates with other leading research groups in Malmö and Aarhus, via the Scandinavian Center for Orofacial Neuroscience (SCON). The group also has a close collaboration with the Specialist Clinic for Orofacial Pain at the Eastman Institute in Stockholm. Group members and projects follow below.
Group members
- Malin Ernberg, DDS, PhD, professor
- Nikolaos Christidis, DDS, PhD, associate professor
- Britt Hedenberg-Magnusson, DDS, PhD, associate professor
- Sofia Louca Jounger, DDS, PhD
- Hajer Jasim, DDS, PhD
- Samaa Al Sayegh, DDS, PhD Student
- Abdelrahman Alhilou, DDS, MSci, PhD Student
- Malin Collin, DDS, PhD Student
- Golnaz Barjandi, DDS, PhD student
- Maria Erkapers, DDS, PhD student
- Ioanna Vasilatou, DDS, MSci student
- Raghdah Abduljabbar, DDS, MSci student
Pain genes and muscle biomarkers in TMD myalgia

PI: Malin Ernberg
In this clinical/experimental study we investigate the role of algogenic inflammatory markers and their genes in the pathophysiology underlying TMD myalgia in clinical and experimental studies using e.g. intramuscular microdialysis, blood and saliva samples. The project started 2010 and has so far resulted in a PhD thesis with several publications.
Group members: Sofia Louca Jounger, Nikolaos Christidis
Collaborations: Professor Martin Schalling, KI; Professor Peter Svensson, Aarhus University.
Molecular biomarkers in saliva in health and pain states

PI: Malin Ernberg
The overall aim is to investigate saliva levels of algesic and inflammatory markers in TMD pain. Saliva levels of 5-HT, glutamate, nerve growth factor (NGF), substance P (SP), calcitonin gene-related peptide (CGRP), and brain derived neurotrophic factor (BDNF) as well as the whole proteome is compared between patients with TMD myalgia and healthy controls. The project started 2012 and has so far resulted in a PhD thesis with several methodological and clinical publications.
Group members: Hajer Jasim, Britt Hedenberg-Magnusson
Collaboration: Associate Professor Bijar Ghafouri and Professor Björn Gerdle, Linköping University, Sweden; Professor Jochen Schwenk and PhD Claudia Fredolini, Royal Institute of Technology, Stockholm, Sweden.
The role of the kynurenine pathway and oral microbiota in chronic muscle pain
PI: Malin Ernberg
The aim of this project is to explore if a shift in the tryptophan metabolism and salivary microbiome participates in the pathogenesis of chronic musculoskeletal pain and includes patients with TMD myalgia and myofascial pain as well as fibromyalgia. Methods involve intramuscular microdialysis and blood samples that are analyzed with novel techniques. The project started 2018.
Group members: Golnaz Barjandi, Britt Hedenberg-Magnusson
Collaboration: Professor Eva Kosek, Professor Sophie Erhardt and Professor Georgios Belibasakis, KI.
Jaw motor control in patients with severe tooth wear
PI: Malin Ernberg
The project aims to investigate different aspects of jaw motor control, jaw function and oral health impact on quality of life in patients with severe tooth wear before and after comprehensive oral rehabilitation. In this project, novel technologies are used influences from a prosthetic intervention concerning parafunction, temporomandibular symptoms, and oral health impact on quality of life is unclear and is desirable to clarify. The project started 2019.
Group members: Maria Erkapers
Collaborations: Professor Peter Svensson, Aarhus University; PhD Susanna Segerström, Uppsala University.
Expression of pain receptors and proteomics in healthy and painful human muscle tissue

PI: Nikolaos Christidis
The aim of the project is to investigate if muscle pain is associated with changes in expression of peripheral pain receptors and the muscle proteome. The project includes clinical and human experimental studies in which muscle microbiopsies are taken and analyzed with immunohistochemistry, in-situ hybridization and proteomics. The project started 2015.
Group members: Abdelrahman Alhilou, Malin Ernberg
Collaborations: PhD Akiko Shimada, Osaka University, Japan; Professor Brian Cairns, University of British Columbia, Canada; Professor Peter Svensson, Aarhus University, Professor Camilla Svensson, KI.

Mastication in Jaw Muscle Pain

PI: Nikolaos Christidis
This project investigates if acute or chronic pain in the orofacial muscles or temporomandibular joints affect the human biting behavior or if absence of sensory input does affect the human biting behavior. It is a clinical/experimental study using patients and experimental pain settings, analyzing biting and chewing behavior with jaw-tracking, muscle EMG, and chewing performance by mixing and splitting different foods.
Collaborations: PhD Anastasios Grigoriadis, PhD Krister Svensson, and PhD Abhishek Kumar, DentMed, KI. PhD Lars Fredriksson, Eastman Institute, Stockholm.
Orofacial pain and jaw function in children and adolescents

PI: Nikolaos Christidis
This multi-center project aims to investigate the prevalence, incidence, risk-factors, and knowledge-base among care-givers regarding temporomandibular disorders. Also, to investigate the effectiveness of different treatment modalities in children with primary or mixed dentition suffering from either TMD myalgia or arthralgia, and if these treatment modalities have any adverse effects on the mandibular development/growth.conducted in the Public Dental Health in Stockholm and Linköping. The project started 2019.
Group members: Raghdah Abduljabbar, Ioanna Vasilatou, Sofia Louca Jounger.
Collaborations: PhD Georgios Tsilingaridis; PhD Lars Fredriksson, Senior Consultant Mathias Lemberger, Eastman Institute, Stockholm, Associate professor Pernilla Larsson-Gran, Folktandvården Druvan, Östergötland, PhD Amal Al-Khotani, Jeddah University, Saudi-Arabia.
Learning dental and nursing literacy as part of professional knowing in academia
PI: Nikolaos Christidis
This is an observational study using interviews with thematic analysis that aims to map and analyze Swedish dental students’ writing in an academic setting, i.e. what these students are expected to read and write, how they are expected to read and write, and what they write.
Group member: Sofia Louca Jounger.
Collaborations: PhD Viveca Lindberg, Stockholm University; PhD Maria Christidis, Red Cross University College, Huddinge.
Prediction of disease activity and TMJ in patients with juvenile idiopathic arthritis
PI: Britt Hedenberg-Magnusson
In this project we will evaluate the potential usefulness of the diagnostic criteria Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) in combination with panoramic and CT imaging in monitoring disease activity and severity in TMJ involvement in children and adolescents with JIA. We also aim to valuate if analyses of potential salivary biomarkers can be a useful tool in monitoring disease activity in JIA in general. The project stared 2013.
Group members: Malin Collin, Nikolaos Christidis, Malin Ernberg
Collaborations: Associate Professor Stefan Hagelberg, KI; Professor Thore Larheim and PhD Linda Arvidsson, Oslo University, Norway
Research support
- Clinical Scientist Training Program KI (Golnaz Barjandi).
- Region Stockholm/KI – SOF
- Region Uppsala
- The Swedish Dental Association
- The Swedish Rheumatism Association
- Ministry of Health, Saudi Arabia